Method for recycling oilfield and other wastewater

ABSTRACT

The present invention pertains to a process for treating waste water from mining. The process involves contacting the mining waste water with an emulsion of a nano scale compound comprising iron, magnesium, or both. Mixing results in a substantially foam-like layer at the surface of the mixture which may be further oxidized to form treated water.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.15/110,339 filed Jul. 7, 2016 from PCT/US2015/010,902 filed Jan. 9, 2015claiming priority to provisional application No. 61/925,585 filed Jan.9, 2014, provisional application No. 61/942,555 filed Feb. 20, 2014, andprovisional application 61/980,351 filed Apr. 16, 2014. The applicationalso is related to and claims priority from U.S. Ser. No. 15/11,247filed Jul. 7, 2016. All of the foregoing are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a method and chemical process for wastewater treatment. In particular, the process relates to, for example,reducing the TDS (total dissolved solids), sodium chloride, cyanides,ammonia compounds, total nitrogen, sulfates, phosphorus and mixturesthereof, extracting heavy metals, and degrading volatileorgano-chlorides (VOC's), water-soluble organics, and/or petroleumhydrocarbons (PHC's) of a waste water solution. This makes the waterrecyclable and more environmentally friendly to use.

BACKGROUND AND SUMMARY OF THE INVENTION

The current demand for water, water management and water treatmenttechnologies is directly related to the increase in oil and gas demandsin the emerging shale plays in the USA and international markets. Inparticular, oil shale plays and liquid rich plays will make up asignificant portion of the energy mix in addition to water flood drivesand other enhanced oil recovery (EOR) methods to extract from olderfields. In most cases, improved, enhanced and unconventional methods,water is injected and therefore water and water management are keyfactors for energy production.

Unfortunately, in many parts of the USA and other markets where oil andgas operations are performed, water can be limited. The oil and gasindustry is now considering ways to reduce fresh water consumption, andto recycle waste water as well as oil and gas produced or flow backwaters.

Typically, waste water cannot be safely released into the environment orreused for other processes or applications until the main contaminateshave been removed. There are a number of waste water sources fromagriculture, mining—AMD (acid mine drainage), quarries, others and inparticular, oil & gas industries, such as shale fracking operations.Waste from shale operations is of significant importance in theseunconventional gas and oil plays.

Shale plays cannot be economically commercialized without beingfractured, which usually involves large volumes of water and proppant tokeep the fractures open after treatment. This significant water needoften becomes problematic because of limited fresh and saline wateravailability, volume required, transportation cost and issues,containment and spill concerns, and increasing regulatory pressures.Each well can require up to 250,000 barrels, i.e., 10,500,000 gallons ofwater. During well testing, as much as 40% of the fluid pumped duringthe fracturing procedure is returned in the first 3-4 weeks of welltesting. Often, water continues to be produced during the lifetime ofthe well. These waters are referred to as flowback and/or producedwater. Contaminates in these fluids may include chlorides, surfactants,sulfates, boron, polymer, sand, silt, clays, heavy metals, oils,condensate, biocides, and/or other elements of environmental concern.

Current fluid disposal methods can be costly due to transportation andthese fluids are often simply pumped into a salt water disposal wellwhere they are permanently depleted from the ecological system. Currenttreatments of these fluids are often limited due to costs andefficiency. Treatment costs are usually directly associated with theamount of total dissolved solids in solution and many applications, suchare reverse osmosis, are often limited due to the amount of solids insolution. Distillation to clean water is similarly limited by the amountof process water it produces before the water reaches saturation andsalts precipitate. Other examples of fluid treatment on these watershave included, electrocoagulation, oxidation, chemical precipitation,macro or nano and ultra filtration, ion-exchange, forward osmosis,evaporation and even dilution with fresh water sources. Such treatmentssuch as ion exchanges or chemical softening or precipitation often donot directly alter the TDS or total dissolved solids, do not degrade orremove VOC's, water soluble organics, PHC's and/or heavy metals of thesolutions. Thus, new waste water treatment methods are needed whichreduce the TDS (total dissolved solids), extract heavy metals, anddegrading volatile organo-chlorides (VOC's), water soluble organics andpetroleum hydro-carbons (PHC's) of a waste water solution.

Similarly, new water treatment methods are needed with respect toagricultural waste water. Such agricultural waste water commonly resultsfrom, for example, pig or hog farms, chicken farms, fish or shrimpfarms, milk or dairy farms, and to a lesser extent cattle ranching. Thecontaminants of agricultural waste water differ depending upon the typeof agriculture but may include, for example, high organic content, highsolids, nitrogen compounds such as nitrates, phosphorus compounds,antibiotics, hormones, copper, etc. Such waste water is believed tocontribute to a higher mortality rate for the animals and is also oftenaccompanied by noxious odors. Accordingly, new treatment methods toreduce one or more the aforementioned contaminants and/or associatedodors would be beneficial.

Likewise, hardrock mines such as gold, copper, uranium and the likegenerate significant amounts of waster water. Some estimates suggestthere are from 17 to 27 billions of gallons of mining-related wastewater in need of treatment. This waste water often comprises suchcontaminants as ammonias, cyanides, arsenic, cadmium, chromium, mercury,lead, nickel and the like. Moreover, treating mining-related waste wateris often challenging

Advantageously, the present invention often meets all the aforementionedneeds and more. In one embodiment the invention relates to a process fortreating waste water. The process comprises contacting the waste waterwith an aqueous emulsion. The aqueous emulsion comprises one or moreoil-liquid membranes surrounding a nano scale compound comprising iron,magnesium, or both. Typically, the weight ratio of emulsion to wastewater is from about 1:150 to about 1:3000. The waste water and emulsionis then mixed for a time and under conditions sufficient to lower thesurface tension of said waste water to between about 35 to about 75dynes per cm at 25° C. according to the definition of kilogram-force forall gravitational units. This forms a substantially foam-like layer atthe surface of the mixture. The foam-like layer is removed from themixture such that the mixture comprises treated water.

In another embodiment, the present invention pertains to a process fortreating waste water. The process comprises first removing at least asubstantial portion of any floating oil and solids from the waste waterto form pre-treated waste water. The pre-treated waste water is providedto a conduit connected to an open or closed vessel in a manner such thatthe pre-treated waste water moves through the conduit to the openvessel. An aqueous emulsion is injected into the conduit at one or moreinjection points wherein the aqueous emulsion comprises one or moreoil-liquid membranes surrounding a nano scale compound of iron,magnesium, or both. The weight ratio of emulsion to pre-treated wastewater is typically from about 1:150 to about 1:3000 and the residencetime in the conduit is at least about 1 minute up to about 30 minutes.The conditions are such that the surface tension of said waste water islowered to between about 35 to about 75 dynes per cm at 25° C. accordingto the definition of kilogram-force for all gravitational units prior tosaid pre-treated waste water entering said open vessel. An oxidizingagent is then contacted with the waste water in the open or closedvessel under conditions sufficient to form a substantially foam-likelayer at the surface of the open or closed vessel and treated waterbelow. The substantially foam-like layer at the surface of the open orclosed vessel is then separated from the treated water.

DETAILED DESCRIPTION

In one embodiment the invention relates to a process for treating wastewater comprising dissolved solids. The source and type of waste water isnot particularly important so long as it contains TDS (total dissolvedsolids), heavy metals, volatile organo-chlorides (VOC's), water solubleorganics, and/or petroleum hydro-carbons (PHC's) which are capable ofbeing reduced or removed with the present inventions. Any type ofwastewater may benefit from the present invention.

Typically, the source of water is a produced fluid from an oil or gasoperation such as fracking. Such produced fluids often have one or morecontaminants which may be reduced or removed by the processes of thepresent invention. Such contaminants may include, but are not limitedto, boron, barium, chlorides, dissolved solids, iron, lead, and/orcadmium. The amounts of each, if present, vary depending upon thewastewater to be treated. Typical waste water varies widely with respectto total dissolved solids but may range from 300 to 250,000 ppm or more.Using the processes of the invention one may reduce these as much asdesired and typically below about 3000, below about 1000, or even belowabout 500 ppm if desired.

Alternatively, the source of water to be treated is an agriculturalwaste water such as, for example, water from pig or hog farms, chickenfarms, milk or dairy farms, or even cattle ranching. The contaminantswill vary depending upon the type of agriculture from which the water isderived. However, most agricultural waste water will derive at leastsome benefit from treatment according to the instant invention.

Recycling the waste water and converting it to meet or exceed theagricultural, e.g., livestock, water quality guidelines according tocertain embodiments of the invention may in some instances reduce themicroorganisms to, for example, fewer than 100 total bacteria permilliliter. In other embodiments, microorganisms may be reduced to, forexample, fewer than 50 coliforms per milliliter of water. Physicalmeasurements for treated agricultural, e.g., livestock, waste water mayinclude that the water should be substantially clear and substantiallyodorless according to a simple visual and odor test. In otherembodiments, treating agricultural, e.g., livestock, water according tothe present methods may result in one, two, three, four, five, or evenall six of the following: (1) total dissolved solids below about 500mg/l; (2) pH of from about 6.5 to 8.5; (3) ammonia less than about 1ppm; (4) nitrates below about 10 ppm; (5) chlorides below about 250 ppm;and/or (6) heavy metals below about 0.1 ppm according to conventionaltests such as, for example, those described herein. Advantageously, theagricultural waste water treatment methods of the present invention canoften be employed to meet applicable standards without the use ofbiocides and the like.

The waste water is first contacted with an emulsion. However, beforedoing so or simultaneously therewith it may be desirable to remove atleast a substantial portion of any floating oil, solids, or mixturethereof from the waste water. The specifics of such removal are notparticularly critical and thus may be accomplished in any convenientmanner to form pre-treated water that is substantially free of floatingoil and solids. Convenient manners of such removal may include, forexample, mechanical methods such as sifting, skimming, or filtration, aswell as, using adsorbents and the like.

In addition, before contacting the waste water with the emulsion orsimultaneously therewith it may also be beneficial to conduct a simpleoxidation of the waste water. In this manner, a majority of readilyremovable water phase PHC's, chlorides, boron, barium and transitionalmetals (such as iron, lead, cadmium, etc.) are reduced and/or removed.If desired, total suspended solids and iron may also be reduced and/orremoved prior to contacting the waste water with the emulsion.

The waste water is contacted with the emulsion in any convenient mannerand such method of contact may vary depending upon the specificequipment, specific waste water composition, and specific emulsion.Advantageously, the processes are useful over a wide range oftemperatures. Typically, the temperatures employed are such that theemulsion is readily capable of pumped. Depending upon the specificemulsion such temperature is usually at least about 50, or at leastabout 60, or at least about 65° F. On the other hand, the temperaturesare not so high that the wastewater evaporates or the emulsion degradesprior to functioning properly. Because the wastewater typically containssalts and other dissolved salts, the wastewater's boiling point may behigher than conventional water. In this manner, temperatures as high as300° F. may sometimes be employed. Typically, the temperatures employedare below about 200, or below about 180, or below about 170° F. The wideuseful temperature range is advantageous in that often produced fluidsare above about 100° F. and can still be contacted directly with theemulsion without requiring any cooling. The wide useful temperaturerange is advantageous for agricultural waste water in that it is oftenin a pond or holding tank exposed to outdoor air temperatures that canvary widely with the season and geographic location.

In one embodiment, untreated or pre-treated waste water is provided to aconduit which is connected to a vessel in a manner such that thepre-treated waste water moves through the conduit to the vessel. Thevessel is typically an open or closed vessel of any shape anddimensions. The emulsion is injected into the conduit at one or moreinjection points. Such injection point may be at the opening of theconduit or along the path of the conduit. That is, the manner of contactvia injection point or points other otherwise is not particularlycritical so long as the emulsion and waste water are subsequently mixedappropriately. Such mixing will necessarily vary depending upon theselected equipment but is usually mechanical mixing such as with apaddle or other stirring mechanism. Alternatively, in the case of aconduit and an open or closed vessel appropriate mixing may occur simplyby virtue of the turbidity caused by the injection. Alternatively,mixing by, for example, a static mixer with some sort of dedicated pathmay be employed.

In some instances enhanced mixing techniques may be useful or desirable.That is, methods or apparatuses may be employed to provide moreturbulent flow than the conventional mixing techniques described above.Such methods and apparatuses may include, for example, split streamscolliding in a mixing chamber, rotational cavitation, static or otherenhanced mixing and combinations thereof. If desired, one or moreoxidizers may be used with or without the enhanced mixing techniques.Such oxidizers include, for example, air, ozone, hydrogen peroxide,nanoscale bubbles, nanoscale sparge tubes or other apparatus ortechnique to control bubble size.

In another embodiment which may be particularly applicable to wastewaterat, for example, pig, chicken, or agricultural farms, the waste water istreated via misting it with the emulsion. Any misting system capable ofeffectively delivering the emulsion in the desired amounts to the wastewater may be employed. In addition or as an alternative to a manuallycontrolled system, a misting system could be controlled electronically.In this manner, it could be activated via timers and/or via sensors suchthat it is turned on or emulsion amounts adjusted based on the level ofcertain contaminates in the waste water. If desired, in someapplications a dewatering box may be employed to process solid wastesfrom or washed from, for example, livestock housing.

The weight ratio of emulsion to untreated or pre-treated waste watervaries depending upon the composition of the untreated or pre-treatedwaste water, emulsion, desired final product, and other conditions. Ithas been found that weight ratios of emulsion to untreated orpre-treated waste water of at least about 1:150, or at least about1:250, or at least about 1:750, or at least about 1:1000, or at leastabout 1:1250 are often useful. On the other hand, weight ratios ofemulsion to untreated or pre-treated waste water of less than from aboutto about 1:3000, or less than about 1:2500, or less than about 1:2000are useful.

As with produced water from oil and gas operations, in agriculturalapplications the weight ratio of emulsion to waste water also variesdepending upon the specific agricultural application, the composition ofthe untreated or pre-treated waste water, emulsion, desired finalproduct, and other conditions. For example, in some agriculturalembodiments there may be different ratios depending upon whether theemulsion is being used for routine maintenance or treatment of somespecific level of contaminant such as organochlorides. That is, in somecases for maintenance the weight ratio of emulsion to waste water may befrom about 1:2000 to about 1:2500. On the other hand, if used fortreatment of contaminants then the weight ratio of emulsion to wastewater may be from about 1:250 to about 1:1250 with higher amounts ofemulsion used for treating higher levels of organochlorides.

Of course, the agricultural applications are not limited to livestockand can also be used for aquatic applications such as shrimp and fishfarms. In such applications, the ratios also vary depending upon thetype of fish or shrimp, the contaminants, environmental conditions andthe like. However, in many cases aquatic applications may employ aweight ratio of emulsion to water of from about 1:3000 to about 1:5000.

The contact and mixing conditions differ depending upon the reactantsand other conditions employed. That is, any convenient conditions may beemployed so long as a substantially foam-like layer is subsequentlyformed at the surface of the mixture. Typically, the contact time forthe waste water and emulsion are such that the surface tension of saidwaste water becomes below about 75, or below about 50 dynes per cm, downto about 45, or down to about 35 dynes per cm at 25° C. according to thedefinition of kilogram-force for all gravitational units. That is, if aconduit and open or closed vessel are employed then there is sufficientmixing and time for the surface tension to be lowered below about 75, orbelow about 50 dynes per cm down to about 45, or down to about 35 dynesper cm at 25° C. according to the definition of kilogram-force for allgravitational units prior to said pre-treated waste water entering saidopen vessel. Typically, if pumping is to be employed, then it may beeasier to pump at between about 45 to about 65 dynes per cm at 25° C.

The mixing time also varies depending upon the equipment, reactants, andother conditions employed. Generally, mixing time is less at highertemperatures. At typical or ambient temperatures using a conduit andopen vessel, the residence time in the conduit is usually at least about1 minute, or at least about 3 minutes, or at least about 5 minutes, upto about 60 minutes, or up to about 45 minutes, or up to about 30minutes. For processing of water in, for example, open ponds as may donein agricultural applications the emulsion may be pre-mixed withwastewater in a small tank prior to discharge in the pond.

The aqueous emulsion employed may vary depending upon the reactants,equipment, and conditions employed, as well as, the desired results. Thespecific emulsion is not particularly critical so long as it results ina substantially foam-like layer formed at the surface of the mixture ofthe emulsion and waste water. Typically, the emulsion comprises one ormore oil-liquid membranes surrounding a nano scale compound of iron,magnesium, or both. In many instances it is preferable that the emulsioncomprises one or more food grade plant oil-liquid membranes surroundinga nano scale compound of iron, magnesium, or both.

The nano scale compound of iron, magnesium, or both may be any that iscapable of being encapsulated, i.e., surrounded, by one or moreoil-liquid membranes. The nano scale compound is typically selected fromthe group consisting of chelated iron, chelated magnesium,iron/magnesium, zero valent magnesium, zero valent iron, or a mixturethereof. By nanoscale is meant particles wherein the mean diameter ofthe metal particles is at least about 50, or at least about 75, or atleast about 100 nm up to about 600, or up to about 500, or up to about400 nm. By “food grade plant oil-liquid membrane” is meant asubstantially hydrophobic membrane comprised of biodegradable surfactantand biodegradable oil. In this manner, when water is employed withbiodegradable surfactant, biodegradable oil, and the nanoscale compound,then an aqueous emulsion is formed.

The aforementioned aqueous emulsions may be prepared in any convenientmanner. Typically, an emulsion is made by first acquiring or making ametal compound, i.e., emulsion precursor. For example, a chelated ironprecursor is prepared by mixing nanoscale chelated iron, water, and achelating agent and heating it to form a slurry. A chelated magnesiumprecursor may be made by mixing water, base such as sodium hydroxide,and nanoscale magnesium. An iron/magnesium precursor may be made bymixing nanoscale magnesium, hot iron, and one or more surfactants suchas polysorbates and/or fatty acid esters such as sorbitan esters.Similarly, a zero valent magnesium precursor may be made by mixingwater, a base such as sodium hydroxide, nanoscale zero valent nanoscalemagnesium, and one or more surfactants such as polysorbates and/or fattyacid esters such as sorbitan esters while zero valent iron precursor maybe made by mixing water, a mineral acid, nanoscale zero valent iron, oneor more surfactants such as polysorbates and/or fatty acid esters suchas sorbitan esters.

Once the metal precursor is formed it is typically added by itself orwith other precursors to non-ionic surfactants and emulsifiers withvigorous mixing. The type and amount, if any, of added surfactants andemulsifiers depends in many cases on the amount in the precursor(s). Aparticularly preferable emulsifier may include alkylamine linear alkylaryl sulfonates. The type and amount of metal compound in the emulsionvaries depending upon target contaminate(s) of the wastewater.Typically, the weight of the metal compound in the emulsion is at leastabout 0.05, or at least about 0.08, or at least about 0.1 weight percentbased on the total weight of the emulsion. On the other hand, the weightof the metal compound in the emulsion is not so much that it wouldinterfere with the treatment process or cause significant environmentalissues. In most cases, the weight of the metal compound in the emulsionis less than about 15, or less than about 8, or less than about 5, orless than about 3 weight percent based on the total weight of theemulsion.

A particularly useful emulsion may be prepared by encapsulating ananoscale Mg₂FeH₆ into an emulsifier and water to form an intermediate.The intermediate may then be mixed with one more linear anionicsurfactants to form the emulsion.

Methods of making emulsions of zero-valent iron are described in, forexample, U.S. Pat. No. 6,664,298 which is incorporated herein byreference. Typical oil-liquid membranes may be formed by any convenientingredients so long as the metal compound is isolated from oxygen inwater carrier. This can be done by, for example, utilizing chemical andhigh impact blending of Tween 80™ (polysorbate 80), Tween™ 20(polysorbate 20), and/or Span™ 85 (Sorbitan Trioleate). This is thenmixed with water and nanoscale chelated iron, chelated magnesium, zerovalent magnesium, zero valent iron, or iron/magnesium to formhydrophobic emulsion droplets (micelles) that are infused into ahydrophilic emulsion droplet from, for example, modified linear anionicsurfactant further mixed with a nonionic surfactant such as Tomadol™1200. Suitable anionic surfactants may include, for example,alpha-sulphonated methyl esters from a suitable vegetable oil, palm oil,soy oil, or hydrocarbon oil. Suitable hydrocarbon oils includesynthetic, olefin, esters, non-water soluble alcohols such as 2-ethylhexanol and the like. In this manner, the emulsion is often misciblewith the targeted compounds in the waste water.

Using the instant description the skilled artisan can formulate anemulsion based on the desired specific contaminants to be reduced oreliminated in the waste water. While not wishing to be bound to anyparticular theory it is believed that the above-described emulsiontemporarily protects the nanoscale compound from oxidizers. It isbelieved that chlorinated volatile organic compounds diffuse through theoil membrane and undergo abiotic reductive dechlorination in thepresence of, for example, the nano scale compound of iron, magnesium, orboth in the interior aqueous phase. That is, encapsulating the nanoscale compound of iron, magnesium, or both in a hydrophilic membraneprotects the nanoscale metal compound from oxygen and other ground-waterconstituents such as inorganics that might foul its reducingcapabilities. In this manner, the composition of the wastewater solutionmay be altered based on the TDS levels and final characteristicsdesired.

The emulsion is contacted with the waste water as described above toform a substantially foam-like layer at the surface of the mixture. Foragricultural applications it may not be necessary to form and/or removea foam-like layer. That is, simple treatment via mixing may be employed.If desired, an oxidizing agent may be employed by, for example,supplying an oxidizing agent such as oxygen in the form of, for example,by applying a feed, e.g., continuous or via one or more bursts, of air,ozone, peroxide, or other oxygen containing gas. Other oxidizing agentsmay also be employed in the present invention in gas or powder form. Forexample, an anionic component of a salt such as, for example, metalsalts of chromates and dichromates, chlorates and perchlorates,nitrates, perborates, perchloric acid (below 70% concentration) andhydrogen peroxide. Also, salts such as alkali or alkaline earth metalsalts of hypochlorite, permanganate, and peroxide may be employed suchas chromium trioxide, hydrogen peroxide, halane, and nitric acid. Aparticularly useful agent may be sodium permanganate. Other oxidizersinclude ammonium dichromate, potassium chlorate, hydrogen peroxide,calcium hypochlorite, sodium chlorate, perchloric acid, sodium chlorite,and potassium bromate. Others may include ammonium perchlorate, ammoniumpernitrate, and potassium superoxide. As described above, enhancedmixing techniques may be useful or desirable with or without one or moreof the oxidizers.

The process steps and process may be employed batch-wise orcontinuously. Advantageously, the resulting treated water after removingor otherwise separating the foam-like layer in any convenient manner mayreduce total dissolved solids as much as desired and typically belowabout 3000, or even below about 500 ppm if desired. That is, the processmay be repeated as necessary to obtain the desired reduction in totaldissolved solids. The treated water can then be treated even further ifdesired with, for example, a reverse osmosis membrane or other filtermedia to further enhance its quality.

Advantageously, the process is useful to eliminate the need for freshwater sources for shale fracturing operations and to recycle producedand flowback waters on site, at an impoundment, a salt water facility,or other locations at reduced costs and footprint of currenttechnologies. This reduces or even eliminates the risk of potentialspills during storage and/or transportation of salt water brine throughpipes, hoses, and ground transport. It also allows for efficient andsafe reuse on site or elsewhere.

Treatment of Mining-Related Wastewater

As described above, treatment of mining-related wastewater is complexdue to the amount of water to treat, the specific contaminants such ascyanides, heavy metals, sulfides, sulfates, volatile organic compounds,and the like. Fortunately, the instant processes are capable of treatingsuch mining-related wastewater effectively and cost efficiently.

The specific process and compositions employed in treatingmining-related wastewater will depend on the contaminants in the wastewater, the compositions and equipments available, and desired results.Generally, the steps involved may include destroying the cyanide,nitrogen, hydrogen peroxide, sulfides and volatile organics, reducingthe total dissolved solids, removing heavy metals, removing chlorides,and oxidizing. The particular order of the steps may or may not becritical depending upon the compositions and equipment employed and thecontaminants to be removed and the desired levels, as well as,environmental conditions. Representative specific processes aredescribed in Examples 7 and 8 below.

Typically, mining water comprises cyanides which need to be removed toform a treated water comprising a free cyanide content below about 5, orbelow about 2, or below about 1 mg/L according to EPA 9016 test.Typically, the mining waste water is contacted with an aqueous emulsioncomprising one or more oil-liquid membranes surrounding a nano scalecompound comprising iron, magnesium or both wherein the weight ratio ofemulsion to mining waste water is from about 1:150 to about 1:3000.Other weight ratios such as those described previously may be employeddepending upon the contaminants. Typically, if there is, for example,higher cyanide content, then an emulsion having more iron may beemployed. The amounts can be calculated by an ordinary skilled artisanin a manner similar to Fenton's reagent calculations.

The waste water is in then oxidized in a convenient manner usingoxidizing agents described previously. A particular suitable agent maybe a composition comprising hydrogen peroxide in a weight ratio of from1:250 to 1:500. The mixture is then blended from at least 5, or at least10, or at least 20 minutes up to about 3 hours, or up to about 2 hours,or up to about 1 hour. If desired or necessary the pH of the waste watermay be adjusted in a convenient to between 6.8 and 7.4 subsequent tooxidizing. Next, the ammonia may be broken down in any convenientmanner. For example, calcium hypochlorite or sodium thiosulphate may beemployed in a ratio of from about 14:1 to about 4:1 based on nitratecontent. Similarly, if desired to break down the hydrogen peroxide, thenpotassium permanganate or some other compound may be employed insufficient amounts. The specific amounts and times for such reactionsmay be readily determined by the skilled artisan in light of the instantspecification.

If necessary, a further amount of aqueous emulsion comprising one ormore oil-liquid membranes surrounding a nano scale compound comprisingiron, magnesium or both may be added subsequent to oxidizing. Likewise,adding a flocculant or coagulant subsequent to oxidizing may bedesitable. The mixture may be subjected to activated carbon subsequentto oxidizing to remove chlorides. Further oxidation may be conducted ifdesired through, for example, 2 micron spargers.

EXAMPLE 1—CHELATED IRON EMULSION

An aqueous emulsion comprising one or more oil-liquid membranessurrounding a nano scale compound comprising chelated iron is mixed.Specifically, chelated iron may be bought or prepared. Suitable chelatediron compounds are usually in the range of from about 6 to about 12%iron chelated with, for example, an amine such as EDTA(Ethylenediaminetetraacetic acid), EDDHA, and/or DTPA. Specific suitablemolecular formulas include, for example, C10H12N2O8 FeNa.3H2O,C18H16N2.6FeNa, and DTPA.Fe.HNa.

The chelated iron is next mixed with from about 25 to about 65 weightpercent emulsifier and from about 15 to about 50 weight percentnon-ionic surfactant and from about 5 to about 35 weight percent of anester surfactant. Typical emulsifiers include one or more of thefollowing: Branched Dodecyl Benzene Sulfonic Acid, Dioctyl sodiumsulfosuccinate, Isopropylamine Branched Alkyl Benzene Sulfonate,Isopropylamine Linear Alkyl Benzene Sulfonate, Linear Alkyl BenzeneSulfonic Acid, Sodium Alpha Olefin (C12) Sulfonate, Sodium Alpha Olefin(C14-16) Sulfonate, Sodium Branched Alkyl Benzene Sulfonate, SodiumBranched Dodecyl Benzene Sulfonate, Sodium Lauryl Sulfate, Sodium LinearAlkyl Benzene Sulfonate, Sodium Linear Alkyl Benzene Sulfonate Slurry,Sodium Linear Alkylbenzene Sulfonate, Sodium Olefin Sulfonate, SodiumOleic Sulfonate, Triethanolamine Linear Alkyl Benzene Sulfonate.

Useful non-ionic surfactants may include linear ethoxylated alcoholssuch as those called TOMADOL available from Air Products. Typical estersurfactants may include one or more of the following: Glycerolα-Monostearate, Monomyristin, Monopalmitin, Monostearin, PolyethyleneGlycol Monolaurate n≈10, Polyethylene Glycol Monostearate n≈40,Polyethylene Glycol Monostearate n≈2, Polyethylene Glycol Monostearaten≈25, Polyethylene Glycol Monostearate n≈4, Polyethylene GlycolMonostearate n≈40, Polyethylene Glycol Monostearate n≈45, PolyethyleneGlycol Monostearate n≈55, Sorbitan Monopalmitate, Sorbitan Sesquioleate,Sorbitan Monolaurate, Sorbitan Monopalmitate, Sorbitan Monostearate,Sorbitan Monooleate, Sorbitan Sesquioleate, Sorbitan Trioleate,Polyoxyethylene-sorbitan monostrearate, Polyoxyethylene-sorbitantristeanate, Polyoxyethylene-sorbitan monooleate,Polyoxyethylene-sorbitan monooleate, and Polyoxyethylene-sorbitantrioleate.

EXAMPLE 2—CHELATED MAGNESIUM EMULSION

A chelated magnesium emulsion may be made in a substantially similarmanner as in Example 1 except that a magnesium chelate is employedinstead of a chelated iron. Suitable magnesium chelates include fromabout 6 to about 12% magnesium chelated with, for example, EDTA(Ethylenediaminetetraacetic acid) and the like. Other suitable chelatedmagnesium compounds include EDTA-MgNa.H2O.

EXAMPLE 3—ZERO VALENT EMULSIONS

Zero valent magnesium, iron, or mixtures of magnesium and iron are madesubstantially as described in U.S. Pat. Nos. 6,664,298 and 7,037,946which are incorporated herein by reference.

EXAMPLE 4—TREATING PRODUCED WATER

Produced water and flowback water from oil or liquids producing shalesmay have a number of contaminates including, for example, ironcontamination, barium contamination, calcium contamination, strontiumcontamination, sulfate contamination, soluble organic compounds, oilysolids contamination, soluble hydrocarbon contamination, polymer & gelcontamination, solids, clays, sand, silt contamination, salts includingmonovalent, divalent and metal, as well as, scale & corrosioninhibitors. The presence and amount of the above may vary depending uponthe particular well or shale play.

Typical shale in Arkansas, Pennsylvania, and North Texas ranges in totaldissolved solids (TDS) from approximately 1,000-250,000 ppm and varieswith the actual field or shale play. For example, in South Texas TDS maybe 40,000 ppm while in West Texas it may be 100,000 ppm and in, forexample, Pennsylvania it may be 80,000-250,000 ppm. Typically, theinstant process will remove the solids that are larger than about 20microns and reduce the TDS to any desired level and in some cases tobelow about 3000 pmm or, if desired, even below about 500 ppm.Accordingly, an aqueous emulsion of example 1, example 2, or some otheremulsion may be employed to treat wastewater depending upon thecontaminant type, concentration, and desired results.

For produced water treatment, pre-treatment of solids may be employed.This assists in removing, for example, the majority of oil, oily solids,iron laden solids, fines, clays, sand, silt, etc. In this manner,reduced concentrations and amounts of the desired emulsion may benecessary. If operating from a salt water well disposal facility, thesolids in the wastewater may be treated after the wastewater has passedthrough an initial settling system and any wash tanks or gun barrelsthat may be employed for oil separation. Typically, a settling tank isused for treating oil. Oil and brine are separated only by gravitysegregation forces. The clean oil floats to the top and brine is removedfrom the bottom of the tank.

In instances where the waste water may still be oily or have significantsolids it may be useful to treat the oily water by using a corrugatedplate separator, a dissolved air flotation cell, a lamella separator, ahydrocyclone or some combination thereof. A lamella separator orclarifier (inclined-plate clarifier) is designed to remove particulatesand could be used in addition to or in place of a settling tank. Aseries of inclined plates provide a large effective settling area for asmall footprint. The inlet stream is stilled upon entry into theclarifier. Solid particles begin to settle onto the plates and begin toaccumulate in collection hoppers at the bottom of the clarifier unit.The sludge is drawn off at the bottom of these hoppers and the clarifiedliquid exits the unit at the top. A hydrocyclone (often referred to inthe shortened form cyclone) is separates particles in a liquidsuspension based on the ratio of their centripetal force to fluidresistance. If it is desired to further remove solids then a bag filterof 0.2-100 micron could be used or in addition or alternatively, acartridge or other filtration or even a membrane could be employed.

Upon removing solids and oil from the waster water, the emulsion is thenmixed with the wastewater in the concentrations and amounts describedabove. Once treated, a dewatering box or DE press filter may be used tocompress the waste prior to disposal in an approved land fill. Resultsof a typical waste water treatment are shown below. Any byproduct gasessuch as chlorine-containing gases or carbon dioxide may be vented toatmosphere or captured and further processed via scrubbing and the like.

EXAMPLE 5—RESULTS OF TREATING PRODUCED WATER

In a manner similar to the examples above, seven different emulsionsaccording to the invention were used in seven different water trials ata drilling site in Eagle Ford wherein the water to be treated initiallycomprised 24,000 ppm total chlorides and 100,000 ppm TPH. The resultsare shown below.

Chlorobromomethane Non-detectable Carbon tetrachloride Non-detectableDibromochloromethane Non-detectable Chlorobenzene Non-detectableChloroethane Non-detectable Chloroform Non-detectable ChloromethaneNon-detectable 1,1-Dichloroethane Non-detectable 1,2-DichloroethaneNon-detectable 1,1-Dichloroethene Non-detectable cis-1,2-DichloroetheneNon-detectable trans-1,2-Dichloroethene Non-detectable1,2-Dichloropropane Non-detectable cis-1,3-DichloropropeneNon-detectable trans-1,3-Dichloropropene Non-detectable MethyleneChloride Non-detectable 1,1,2,2-Tetrachloroethane Non-detectableTetrachloroethene Non-detectable 1,1,1-Trichloroethane Non-detectable1,1,2-Trichloroethane Non-detectable Trichloroethene Non-detectableVinyl chloride Non-detectable Bromodichloromethane Non-detectable1,2-Dichloroethene, Total Non-detectable

TPH's Amount after treatment C6-C12 500 ppm >C12-C28 500 ppm >C28-C35500 ppm

In a manner similar to the examples above, seven different emulsionsaccording to the invention were used in seven different water trials ata drilling site at Permian Basin wherein the water to be treatedinitially comprised a number of contaminates. BC-1 was a MG₂FeH₆emulsion and bursts of the oxidizing agent O₂ were bubbled in thewastewater as described above. BC-2 was a zero valent iron emulsion andbursts of the oxidizing agent O₂ were bubbled in the wastewater asdescribed above. BC-3 was a chelated iron emulsion and bursts of theoxidizing agent O₂ were bubbled in the wastewater as described above.BC-4 was a zero valent magnesium emulsion and bursts of the oxidizingagent O₂ were bubbled in the wastewater as described above. BC-5 was azero valent magnesium emulsion and bursts of NO₂ were bubbled in thewastewater as described above. BC-6 was a zero valent iron emulsion andbursts of NO₂ bubbled in the wastewater as described above. BC-7 was achelated magnesium emulsion without oxidizing agent.

Baseline BC-1 reduction BC-2 reduction BC-3 reduction mg/l mg/l % mg/l %mg/l % Barium 24.500 0.557 −97.727 1.430 −94.163 1.520 −93.796 Boron25.400 0.345 −98.642 1.010 −96.024 0.843 −96.681 Chlorides 13.100 1.780−99.986 5.320 −99.959 3.370 −99.974

BC-4 reduction BC-5 reduction BC-6 reduction BC-7 reduction mg/l % mg/l% mg/l % mg/l % 3.010 −87.714 3.280 −86.612 6.600 −73.061 3.220 −86.8571.500 −94.094 2.690 −89.409 2.050 −91.929 1.180 −95.354 5.150 −99.9616.210 −99.953 7.100 −99.946 3.730 −99.972

EXAMPLE 6—RESULTS OF TREATING AGRICULTURAL WATER

Contaminated soil from a chemical plant was treated using an emulsionsimilar to the one used in the examples above. The soil was saturatedwith water and treated with emulsion. The various chemicals were thenmeasured in the water with conventional techniques and the resultsreported below in the liquid result column. The water was thenevaporated and the soil was kept in an N2 environment for seven days.The various chemicals were then measured and the results reported in thesoil result anaerobic 7 days column. Next, the soil was kept in an O2environment and the various chemicals were measured and the resultsreported in the soil result aerobic 14 days column. The amounts in thetable are reported in parts per billion.

Test Description Base - Soil Result Soil Result Soil Result SW-846 8081AHC-24-2 Liquid Anaerobic 7 days Aerobic 14 days. 4,4′-DDD, Solid 27,0009.0 8,000 6,100 4,4′-DDE, Solid 24,000 1.0 0 0 4,4′-DDT, Solid 40,0000.0 0 0 Aldrin, Solid 26,000 0.0 0 0 alpha-BHC(alpha-Hexachlorocyclohexane), Solid 67,000 1.0 0 0 alpha-Chlordane,Solid 85,000 0.0 0 0 beta-BHC (beta-Hexachlorocyclohexane), Solid 91,00098.0 21,000 5,800 Chlordane, Solid 580,000 44.0 0 0 delta-BHC(delta-Hexachlorocyclohexane), Solid 24,000 0.0 0 0 Dieldrin, Solid26,000 0.0 0 0 Endosulfan I, Solid 24,000 0.6 0 0 Endosulfan II, Solid180,000 0.0 8,000 3,400 Endosulfan sulfate, Solid 34,000 0.0 0 0 Endrinaldehyde, Solid 43,000 0.3 0 0 Endrin ketone, Solid 27,000 0.0 0 0Endrin, Solid 25,000 0.7 0 0 Heptachlor epoxide, Solid 30,000 0.0 0 0Heptachlor, Solid 140,000 0.0 0 0 Methoxychlor, Solid 70,000 0.0 0 0Toxaphene, Solid 18,000,000 45.0 390,000 170,000 gamma-BHC (Lindane),Solid 24,000 0.0 0 0 gamma-Chlordane, Solid 120,000 0.0 1,800 420 Units:μg/l - ppb Units: μg/l - ppb Units: μg/l - ppb Units: μg/l - ppb

EXAMPLE 7—RESULTS OF TREATING MINING WASTEWATER

Mining-related wastewater is pumped through a mixing apparatus, e.g.,Eductor or Chaos Mixer, with a dosing pump adding a zero valent emulsionsuch as zero valent iron and others described in Example 3 above whereinthe ratio of zero valent emulsion wastewater is 1:750. Hydrogen peroxide(35%) or another suitable oxidizer is added at a weight ratio ofhydrogen peroxide to wastewater of 1:500. The mixture is blended for 40minutes. The pH is adjusted in a convenient manner, e.g., adding TCA-SCl(primarily hydroxyacetic acid), to bring the pH down 8 (6.8 to 7.4) oradding sodium bicarbonate or the like to raise pH to the 6.8-7.4 range.Appropriate amounts of sodium thiosulfate or calcium hypochlorite mayalso be added to and blended with the water for a suitable time toachieve significant mixing. The amounts and time will vary dependingupon nitrate content but a typical amount may be from 8:1 sodiumthiosulfate or calcium hypochlorite to nitrate blended for about 50minutes.

The hydrogen peroxide is then broken down in a convenient manner such asby adding an appropriate amount of potassium permanganate to the water.Next, additional zero valent emulsion may be added and sparging employedto break down any remaining cyanides along with sulfides and volatileorganic compounds. To reduce total dissolved solids and remove heavymetals an appropriate amount of a suitable flocculant or coagulant isadded to the water, e.g., iron sulfate, polyaluminum chloride, ironchloride, etc. and blended for a suitable time, e.g., 15 minutes afterwhich settling occurs. The water may then be flowed through a clarifieror a settling containment. If desired, chloride is removed by, forexample, pumping the water through an activated carbon media such as agranular media. The water may then undergo oxidation using, for example,2 micron sparger or other appropriate equipment.

One or more steps or all of the aforementioned steps may be repeated asnecessary to achieve the desired results. Representative results fromthe process are shown in the table below. Mine CTL is mine contaminanttarget level.

Mine Water Laboratory Unit of Mine 1st 2nd 3rd Mine Sample ID MethodMeasure (Baseline) treatment treatment Treatment CTL General ChemistryAmmonia-Nitrogen EPA 350.2 mg/L 1.12 56 11.2 1.12 10 Cyanide Free EPA9016  mg/L 6.50 <0.020 4.90 <0.020 0.1 Cyanide Total 4500CN_C&E mg/L7.85 0.032 4.78 <0.020 1 Total Kjeldahl EPA 351.3 mg/L 2.24 77.3 20.72.80 Nitrogen Total Nitrogen CALC mg/L 2.24 119 21.3 3.36 50 Anions byIon Chromatography Nitrate as N EPA 300.0 mg/L <1.00 21.1 <0.50 0.56Nitrite as N EPA 300.0 mg/L <1.00 20.6 0.63 <0.50 Sulfate EPA 300.0 mg/L86.4 1390 <0.25 98.1 Total Metals Arsenic EPA 200.7 mg/L <0.010 0.0040.002 <0.010 0.1 Cadmium EPA 200.7 mg/L <0.005 <0.005 <0.005 <0.005Chromium EPA 200.7 mg/L 0.021 0.01 0.028 <0.010 Mercury EPA 245.1 mg/L<0.0002 0.0002 <0.0002 <0.0002 Lead EPA 200.7 mg/L <0.010 <0.010 <0.010<0.010 Nickel EPA 200.7 mg/L <0.010 <0.010 0.011 <0.010

EXAMPLE 8—RESULTS OF TREATING MINING WATER

Mining wastewater was treated in a similar manner to Example 7 exceptthat the mining wastewater of Example 8 had different contaminantlevels, e.g., Example 8 wastewater had higher levels of cyanides thanthat of Example 7.

One sample of Example 8 wastewater was treated with a zero valentmagnesium emulsion (nZV-Mg) in a similar process to Example 7, A secondsample was treated with a zero valent iron emulsion (nZVI) in a similarprocess to Example 7 although the zero valent iron emulsion of Example 8comprised a higher amount of iron due to the higher level of cyanides inthe wastewater to be treated. The results are shown below.

Analytical Results, Sample Mine Mining Water Contaminant Before UsingUsing Analysis, mg/L Target Level Treatment nZV-Mg nZVI Alkalinity,CaCO₃ — 120 110 40 CO₃, CaCO₃ — 110 95 <1.0 HCO₃ — <1.0 14 40 Aluminum0.2 <0.045 0.084 0.050 Antimony 0.006 0.0034 0.0095 0.0054 Arsenic 0.0100.20 0.15 0.035 Barium 2.0 0.036 0.023 0.057 Beryllium 0.004 <0.0010<0.0010 <0.0010 Bismuth — <0.10 <0.10 <0.10 Boron — 0.18 <0.10 <0.10Cadmium 0.005 <0.0010 <0.0010 <0.0010 Calcium — 230 36 38 Chloride 400130 130 62 Chromium 0.1 <0.0050 <0.0050 <0.0050 Cobalt — 1.1 0.11 0.094Copper 1.0 0.60 <0.050 <0.050 Cyanide, WAD 0.2 21 0.32 0.12 Fluoride 4.0<1.0 <0.50 <1.0 Gallium — <0.10 <0.10 <0.10 Iron 0.6 0.79 0.21 0.64 Lead0.015 <0.0025 <0.0025 <0.0025 Lithium — <0.10 <0.10 <0.10 Magnesium 1505.0 12 8.6 Manganese 0.10 0.041 <0.0050 0.021 Mercury 0.002 0.012<0.00010 <0.00010 Molybdenum — 0.63 0.20 0.052 Nickel 0.1 0.14 <0.010<0.010 Nitrate as N 340 15 21 Nitrite as N 41 5.1 3.5 Nitrogen, Total asN 10 87 27 7.1 pH, stu 6.5-8.5 9.10 9.73 6.97 Phosphorus — <0.50 <0.500.66 Potassium — 16 8.1 8.7 Scandium — <0.10 <0.10 <0.10 Selenium 0.050.12 0.036 0.024 Silver 0.1 0.50 <0.0050 0.0066 Sodium — 810 220 150Strontium — 2.0 0.35 0.34 Sulfate 500 430 200 120 Thallium 0.002 <0.0010<0.0010 <0.0010 Tin — <0.10 <0.10 <0.10 Titanium — <0.10 <0.10 <0.10Total Dissolved 1000 3,100 890 720 Solids Vanadium — 0.014 0.025 <0.010Zinc 5.0 0.087 <0.010 0.038 Cations, meq/L 47.6 12.6 9.39 Anions, meq/L40.1 11.1 8.34 Balance, % 8.5 6.2 5.9 Wetlab Report # 1509156 15115781511578

The terms and descriptions used herein are set forth by way ofillustration only and are not meant as limitations. Those skilled in theart will recognize that many variations are possible within the spiritand scope of the invention as defined in the following claims, and theirequivalents, in which all terms are to be understood in their broadestpossible sense unless otherwise indicated.

What is claimed is:
 1. A process for treating mining waste water whereinthe process comprises: contacting the mining waste water with an aqueousemulsion comprising one or more oil-liquid membranes surrounding a nanoscale compound comprising iron, magnesium or both wherein the weightratio of emulsion to mining waste water is from about 1:150 to about1:3000; and mixing the mining waste water and emulsion for a time andunder conditions sufficient to lower the surface tension of said wastewater to from about 35 to about 75 dynes per cm at 25° C. according tothe definition of kilogram-force for all gravitational units and form asubstantially foam-like layer at the surface of the mixture; andoxidizing the mixture such that the mixture comprises treated water. 2.The process of claim 1 which further comprises removing at least asubstantial portion of any solids from the waste water prior tocontacting it with the emulsion.
 3. The process of claim 1 wherein thetime of contacting and mixing is from about 1 minute to about 30minutes.
 4. The process of claim 1 wherein the oxidizing is conductedduring or subsequent to mixing.
 5. The process of claim 4 wherein theoxidizing employs an oxidizing agent.
 6. The process of claim 5 whereinthe oxidizing agent is supplied by applying a feed of air, ozone,peroxide, or other oxygen containing substance.
 7. The process of claim5 wherein the oxidizing agent is selected from the group consisting ofmetal salts of chromates, dichromates, chlorates, perchlorates, andnitrates, perborates; perchloric acid; hydrogen peroxide; salts ofhypochlorite, permanganate, and peroxide; sodium permanganate; chromiumtrioxide; halane; nitric acid; ammonium dichromate; potassium chlorate;calcium hypochlorite; sodium chlorate; perchloric acid; sodium chlorite;potassium bromate; ammonium perchlorate; ammonium pernitrate; potassiumsuperoxide; and mixtures thereof.
 8. The process of claim 1 wherein theprocess is conducted on a continuous basis.
 9. The process of claim 1wherein the process is conducted on a batch basis.
 10. The process ofclaim 1 wherein the treated water comprises a total dissolved solidscontent of less than about 1000 ppm.
 11. The process of claim 1 whereinthe treated water comprises a free cyanide content below about 2 mg/Laccording to EPA 9016 test.
 12. The process of claim 1 which comprisesoxidizing the mixture with a composition comprising hydrogen peroxide.13. The process of claim 1 which further comprises adjusting the pH ofthe mixture to between 6.8 and 7.4 subsequent to oxidizing.
 14. Theprocess of claim 1 which further comprises employing potassiumpermanganate subsequent to oxidizing.
 15. The process of claim 1 whichfurther comprises adding a further amount of aqueous emulsion comprisingone or more oil-liquid membranes surrounding a nano scale compoundcomprising iron, magnesium or both subsequent to oxidizing.
 16. Theprocess of claim 1 which further comprises adding a flocculant orcoagulant subsequent to oxidizing.
 17. The process of claim 1 whichfurther comprises subjecting the mixture to activated carbon subsequentto oxidizing.
 18. A process for treating mining waste water wherein theprocess comprises: providing mining waste water to a conduit connectedto a vessel in a manner such that the mining waste water moves throughthe conduit to the vessel; injecting an aqueous emulsion into theconduit at one or more injection points wherein the aqueous emulsioncomprises one or more oil-liquid membranes surrounding a nano scalecompound comprising iron, magnesium, or both, wherein the weight ratioof emulsion to pre-treated waste water is from about 1:150 to about1:3000, wherein the residence time in the conduit is at least about 1minute up to about 30 minutes, and wherein the conditions are sufficientto lower the surface tension of said waste water to from about 35 toabout 75 dynes per cm at 25° C. according to the definition ofkilogram-force for all gravitational units prior to said mining wastewater entering said vessel; and contacting hydrogen peroxide with themining waste water in the vessel in sufficient amounts and underconditions to reduce free cyanide content to below about 2 mg/Laccording to EPA 9016 test.
 19. The process of claim 18 wherein theprocess is conducted on a continuous basis.
 20. The process of claim 18wherein the process is conducted on a batch basis.